Cross-talk ratio

In order to maximize the excitation, precautions have to be taken to avoid cross-talk between excitation and signal. Therefore differential probes are commonly used with a SQUID system Nevertheless, for the discussed defects the SQUID system has a lower excitation field by a factor of about 100 compared with the commereial system This we must keep in mind, when we compare measured signal to noise ratios. There is a potential to improve for small defeets, when eross-talk is managed very well. 

The development of low-dielectric-constant materials as ILDs is crucial to achieve low power consumption, reduce signal delay, and minimize interconnect cross-talk for high-performance VLSI devices. In one of the multilevel interconnect process routes, metal lines (e.g., A1—Cu or Cu) are patterned through reactive ion etching, and then dielectric films are filled in the trenches formed between these lines. These trenches can have widths in the sub-0.5 pm range and aspect ratios greater than 3. Therefore, small gap-filling capability is also required for such dielectrics. 

Elements such as tungsten, zirconium, uranium, and the rare earth elements have multiple spectral lines, which make line selection a difficult task. The degree of interference and sample composition is related to what is called the critical concentration ratio (CCR), which is defined as the ratio of the concentration of interferent i to that of the analyte a at which the ratio of the line intensities IJla is equal to unity. If the measured concentration ratio exceeds the CCR, the intensity of the interferent line will be higher than that of the analyte line and will be detrimental to accuracy. In some spectrometers, optical cross-talk in the region of the exit slit and detector will present itself as a direct overlap. 

Hawn (1983) has described the performance of a dual-anode X-ray source for XPS using various un-collimated and collimated configurations to make it effective in increasing the signal-to-background ratio and reducing anode cross talk without substantial signal loss. 

Undesired effects in fluorescence confocal microscopy can be corrected by ratio imaging. Rati-oing (i.e., the compensation of two channels by digital division) can substantially reduce cross-talk effects in double detectors [63]. Environmental markers indicating the pH value or the level of free calcium ions (Ca"" ) also require ratio imaging to compensate for structural densities or section thickness [19]. 

Instabilities in the feedback system are detrimental to resolution and include poor piezoelectric positioner response, cross talk, and noise. When high aspect ratio features are imaged, the pipette may retract too quickly in the Z direction which can result in lag of the feedback loop. Cross talk can be observed between topographic and current images of a substrate with both conductive and nonconductive features are generated. As the probe is scanned across a sample surface that transitions from nonconductive to conductive, the feedback mechanism assumes the tip is closer to the surface than the set point, which results in a decreased ion current signal. The opposite occurs when the probe is scanned from conductive to nonconductive regions. These effects can be minimized with decreased scan speed and optimized scan parameters. 

Intracavity systems are very sensitive to acoustic cross talk between the modulation unit and the laser resonator, thus increasing the noise just at the modulation frequency / Hence another method of improving the sensitivity of intracavity LMR is to use a lock-in detector at 2/ (the second harmonic), where the noise is considerably smaller. In some cases, this change can increase the signal-to-noise ratio of LMR. 

On a system equipped with multiple RF channels and receivers several such schemes can be executed in parallel. Let s consider one of the simplest NMR experiments - the two-dimensional COSY experiment. The basic homonuclear COSY pulse sequence consists of an excitation pulse followed by the evolution period, t, a read pulse and an acquisition period, t2 (see Fig. 2a). The same scheme can be executed in parallel on two or more RF channels (Fig. 2b). If the cross-talk between the different nuclear species could be avoided, such an experiment would produce two independent 2D COSY spectra. However, in practise the magnetically active and in particular spin 1/2 nuclei from the same molecule are usually coupled via the scalar spin-spin couplings and in such a simple pulse scheme cross-talk is unavoidable. Therefore we should also observe heteronuclear correlations arising ffran coherence transfer A X and X A, i.e. in total four two-dimensional spectra in a single measurement Indeed, all the correlations can be observed in instances where the gyrranagnetic ratios of the nuclei and their natural abundances are similar. In fact, as a cmisequence of the close proximity of the H-1 and F-19 resonance frequencies at the Earth magnetic field, their two-dimensional correlation spectra can be observed even with a single receiver [29]. 

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